As said in my first post, and repeated several times, btcpayserver is great... BUT... it's a seperate setup you have to do (they do have docker images). It's not resource friendly, at least it wasn't when i last set it up.
It required a full node, nbxplorer and on top of that btcpayserver... The resource requirements forced me to quit using btcpayserver when i shut down my dedicated host.

Don't get me wrong: if you want to setup a big store and you plan on accepting a couple thousand dollars in crypto each month, btcpayserver is the way to go. But if you're just testing the waters, and you might (or might not) accept one or two small payments in crypto a month, btcpayserver might not be worth the hassle...

If you're a small operation, you can always use btcpayserver hosted by a thirth party, but then you're trusting somebody else again, and it might not always be free...

I have seen other posts saying there's an integration of payment gateways in shopify. It listed bitpay... I can only say that bitpay is not wel liked in the community. Here's a small list (not mine): https://debitpay.directory/anti-bitcoin/, so if you chose a gateway instead of going non-custodial, please do your homework. Not all gateways are equal!